The global demand for plasma is mainly driven by the requirement for intravenous immunoglobulin (IVIG), the usage of which has grown significantly in different medical areas like neurology, rheumatology, nephrology, dermatology, oncology, infectious diseases, allergy and immunology. With markets projected to grow at 7% to 13% annually, between now and 2020, more IVIG will have to be manufactured to meet the growing demand. Plasma being a scarce and exclusive commodity, there is a continuous need to upgrade and optimize the fractionation processes to maximally utilize this valuable resource. By continuously refining the existing processes, improvements can be achieved by way of process efficiencies, quality of end products and manufacturing yields. In the case of IVIG, increased yields can lead to increased market availability of a product that is the key driver of the plasma fractionation industry.
Majority of the IVIG manufacturers still prefer the classical method of producing IVIG that employs ethanol fractionation at least for the initial steps in the manufacturing process, although chromatography methods are slowly gaining ground. Classical manufacturing processes of IVIG using ethanol precipitation and the new strategies that can increase the practicability and yield of IVIG have been discussed by Andrea Buchacher and Gunter Iberer in Biotechnol. J. 2006, 1, 148-163. The classical Cohn's process of ethanol precipitation (Cohn, E. J., Strong, L. E., Hughes, W. L., Mulford, D. J., Ashworth, J. N., Melin, M., Taylor, H., L.; J. Am. Chem. Soc., 1946, 68, 459-475) succeeds in enriching the five most abundant proteins in fractions I to V by sequential precipitation, by increasing the concentration of ethanol at each step. Fibrinogen is precipitated in fraction I, γ-globulins in fraction II, lipid bearing β-globulins in fraction III, α-globulins in fraction IV and albumin in fraction V. Fraction II and III is the starting material for most IVIG processes. In IVIG manufacture, most manufacturers commonly rely on the initial step of ethanol precipitation and fractionation of plasma, although the later steps may differ from manufacturer to manufacturer. Few continue with ethanol precipitation in the later steps of the process, whereas others may choose to use other precipitation methods like PEG or caprylate or even chromatography.
Although a few chromatography based processes have been described for the production of IVIG without the use of ethanol precipitation, but at the industrial scale, an all-chromatography process scheme has just begun gaining acceptance due to the better quality of the final IVIG product (lesser protein denaturation and aggregation) and better yields (Lontos, J., Chromatographic purification of immunoglobulins at CSL bioplasma; a manufacturing perspective. Plasma Product Biotech meet, 2005; Bertolini, J., Davies, J., Wu, J., Coppola, G., Purification of Immunoglobulins. 1998, WO 98/05686;
US2007049733 discloses ultra-high yield intravenous immune globulin preparation with the use of chromatographic methods in the final purification steps. The ethanol fractionation of plasma was replaced with caprylate or citrate precipitation steps followed by chromatography for purification. The final yields for most of these processes have been in the range of 4 to 6 gm per liter of plasma.
Most of Cohn's and modified Cohn's methods that are in use for the industrial production of IgG have reported yields in the range of 3.5 to 4.2 gm per liter of plasma. This is about 30 to 35% of the total IgG content (12 gm) in human plasma. As this is a high value product for the plasma product manufacturers, many major fractionators have been looking at improvements in their processes to increase yields, by shifting to chromatography based procedures. Substituting chromatography for traditional precipitation steps can not only help to increase yields but also provide a safer and better quality product for human administration.
EP0123029A1 discloses an improved process for the production of a solution of pure IgG-immunoglobulin fraction from natural plasma with unchanged complement-binding activity, which is in the form of a stable, clear aqueous solution for intravenous injection is available. Patent applications JPH09249580A, JPH107588A discloses a method of purification of a crude immunoglobulin-containing fraction and relates it to a process for the pharmaceutical preparation of intravenous immune for intravenous immunoglobulin for infusion using the same purified immunoglobulin. EP0180766, CN103554253, CN103665100, CN102552906, CN102584934 and JP2011102314 disclose processes for preparing human immunoglobulin for intravenous injection. EP2519540, U.S. Pat. No. 6,281,336B1 and CN104004089A disclose methods for producing intravenous human immunoglobulin.
U.S. Pat. No. 6,307,028 discloses a chromatographic method for high yield purification and viral inactivation of antibodies especially of the IgG type from human plasma and other sources.
The present invention discloses an approach to provide an ethanol-free high yielding method for recovering IgG from blood plasma and other blood based materials to the extent of 7 to 8 gm per liter of plasma which is better than the values reported so far in the plasma industry. Besides, the process described ensures that the other therapeutic proteins in the plasma are left untouched and available for extraction from the same plasma pool.